A Heavy Anti-Aircraft Battery was sited at Fort Lytton during WW2. It consisted of four QF 3.7-inch heavy anti-aircraft guns. Each gun was in its own protective emplacement (gun pit) consisting of a polygonal concrete block wall with protective earth piled around the outside. The resulting structure looked like a grassy mound. The four gun pits were sited around a central command post which formed a fifth mound. The command post contained instruments for estimating data such as aircraft speed, height and direction, and an electro-mechanical predictor (computer) which calculated bearing, elevation and fuse-time for the guns.
The battery still exists in relatively good condition about 300m from the Fort Lytton Visitor Centre and inside the perimeter of the Caltex refinery. The above photo was taken in November 2015 and shows the four gun pits.
This Google satellite image was retrieved in October 2016 and shows all four gun pits. The command centre is at the left (western edge) of the site and is largely obscured by a tree.
The following 9 photographs are from the Australian War Memorial. They were taken at Fort Lytton on 11 November 1943 by Ronald Noel Keam. The gunners are from 385th Troop, 6th Australian Heavy Anti-Aircraft Battery.
B191553 GUNNER J. T. GILLON (1); NX106058 BRIGADIER K. T. BULLIVANT (2) AND NX74147 BRIGADIER J. F. SPRINGALL (3).
LEFT TO RIGHT: NX81502 GUNNER W. E. HENNESSEY (1); Q266179 GUNNER V. M. POLLEY (2); NX106058 BOMBARDIER K. F. BULLIVANT (3).
OPERATING A NO. 3 MARK IV TYPE UB7, RANGEFINDER IN THE COMMAND POST. NX106058 BOMBARDIER K.F.BULLIVANT(1); N286152 GUNNER G.STRACHAN(2); N109900 BOMBARDIER M.F.GOODRIDGE(3); QX45416 LIEUTENANT M.J.TAYLOR(4).
OPERATING A PREDICTOR IN THE COMMAND POST. LEFT TO RIGHT: QX52700 GUNNER D.G.INGRAM(1); Q122911 GUNNER E.I.RAILTON(2); QX47321 LANCE BOMBARDIER A.C. JONES(3); Q144265 GUNNER T.J.FALLON(4); NX84178 BOMBARDIER C.F.CUNNINGHAM(5); QX52689 GUNNER J.H.DRIVER(6).
A model of the battery is on display in the Visitor Centre.
THIS LINK shows the Fort Lytton battery as seen on Google. The command post can be seen at the left of the site, partially obscured by a tree.